Table of Content

  

20 October 2011
Volume 46 Issue 10

Articles

Noncommutative geometric approach to quantum spacetime

ZHANG Ruibin1, ZHANG Xiao2

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2011, 46(10):  1-31. 

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Together with collaborators, we introduced a noncommutative Riemannian geometry over Moyal algebras and systematically developed it for noncommutative spaces embedded in higher dimensions in the last few years. The theory was applied to construct a noncommutative version of general relativity, which is expected to capture some essential structural features of spacetime at the Planck scale. Examples of noncommutative spacetimes were investigated in detail. These include quantisations of planefronted gravitational waves, quantum Schwarzschild spacetime and Schwarzschildde Sitterspacetime, and a quantum Tolman spacetime which is relevant to gravitational collapse. Here we briefly review the theory and its application in the study of quantum structure of spacetime.

Mix-valued logic and its applications

CHENG Daizhan, ZHAO Yin, XU Xiangru

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2011, 46(10):  32-44. 

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Mix-valued logic is a natural generalization of Boolean Logic and k-valued logic. It is a new concept proposed by the authors and their research group. It plays an important role in systems control and related fields, and shows it vivid life. The purpose of the paper is to give a systematic survey on the definition, calculation, and main properties of mix-valued logic, and also to normalize the concepts and notations. Using the semi-tensor product of matrices, this paper introducesthe definition of mix-valued logical operators, its calculations, and its basic properties. Then three applications of mix-valued logic are introduced: (1) dynamic game with finite memory of strategies; (2) solving fuzzy relation equations; (3) dynamic-algebraic Boolean networks.

Stage-by-Stage optimization approach to optimal control for general timedelay systems

ZHANG Huan-shui1, SONG Xin-min1, XIE Li-hua2

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2011, 46(10):  45-56. 

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As it is well known that the optimal control of delay-free systems has been well solved with dynamic programming since 60s of last century, however the classical dynamic programming has not been successfully applied to time delay systems so as to derive the controller step by step as for delayfree systems. In this paper, we will propose a stage-by-stage optimization approach to the optimal control problem for general delayed systems by introducing an associated dual backward stochastic system and applying inner-product theory. The proposed approach allows us to complete the square of linear quadratic (LQ) form step by step for the general time delay systems and then present the analytical solution to the controller. It is interesting to show that the controller design for time delay systems is equivalent to the estimator design of different signals from the dual backward stochastic time delay systems.
The proposed general approach is powerful as it allows us to reduce the optimal control for time delay systems from one of determining an entire control sequence at once to one of determining the elements of the sequences singly and recursively. It is trustful that the proposed stage-by-stage approach can be  applied to solve other related complex control problems such as the necessary and sufficient solution to H∞ control and so on.

A survey of cooperative ARQ schemes and cooperative  MAC protocols in multihop wireless networks

LIU Ju, ZHENG Lina

J4. 2011, 46(10):  57-65. 

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The emergence of cooperative diversity not only improves system capacity and effectiveness of resisting to fading, but also provides underlying technical support for cross layer design in Ad Hoc networks. With cooperative diversity introduced into the data link layer, cooperative ARQ schemes, and cooperative MAC protocols have been proposed. In this survey, we review the traditional MAC protocols. Then, the joint problems of medium access protocols and physical layer space diversity in different scenarios for different sakes are discussed. The rules and procedures of the cooperative ARQ and MAC protocols are given, respectively.

A review on streamer waves and associated coronal seismological study

CHEN Yao1, FENG Shi-wei1, SONG Hong-qiang1, LI Bo1, KONG Xiang-liang1, XIA Li-dong1, LI Xing2, LI Gang3,1

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2011, 46(10):  66-74. 

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In this paper, we review our latest studies on a newly-discovered phenomenon dubbed “streamer waves” which are excited in the aftermath of CME-streamer interaction. Streamer waves represent one of the largest wave phenomena ever observed in the solar corona. The wave mode is interpreted as the fast kink body mode supported by and propagating outwards along the plasma sheet of the streamer. With the white light coronagraph data and available observational constraints on the solar wind parameters, we develop a novel seimological technique to diagnose the radial profiles of the Alfv?n speed and magnetic field strength in the region surrouding the plasma sheet structure from 3 to 10 solar radii. We also conduct a data survey searching for welldefined streamer wave events observed by the SOHO／LASCO coronagraph throughout Solar Cycle 23. As a result, eight candidate events are found. We compare different events and find that in most of them the driving CMEs’ ejecta are characterized by a high speed and a wide angular span, and the CMEstreamer interactions occur generally along the flank of the streamer structure at an altitude no higher than the bottom of the field of view of LASCO C2. In addition, all front-side CMEs have accompanying flares. These common observational features shed light on the excitation conditions of streamer wave events.

An introduction to monolithic active pixel sensors

WANG Meng

J4. 2011, 46(10):  75-80. 

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A monolithic active pixel sensor (MAPS) is based on very large scale integration CMOS technology. Its working principles,prototypes, improvements and development trends are introduced in the article.

The preparation, magnetism, and spin-polarized transport of the concentrated magnetic semiconductors

YAN Shishen, MEI Liangmo, CHEN Yanxue, LIU Guolei, SONG Hongqiang, ZHANG Yunpeng, TIAN Yufeng, QIAO Ruimin

J4. 2011, 46(10):  81-85. 

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A series of Zn_1-xCo_xO、Ti_1-xCo_xO₂、(In_1-xCo_x)2O3magnetic semiconductor films with high concentration of the transitional metal Co element (concentrated magnetic semiconductor) were prepared by sputtering machine. The super performance of the materials, such as the high Currie temperature above room temperature, high spin polarization ratio, and large magneto-optical Kerr effect were found in the concentrated magnetic semiconductor films. The electric transport properties were also systematically studied by experiments and theories, and a spin dependent variable range hopping model was proposed. The concentrated magnetic semiconductors are different from the conventional dilute magnetic semiconductors, and they may become good spin injection source and new transparent magneto-optical material.

Research progress in organic spintronics

DONG Xian-feng, QIN Wei, XIE Shi-jie*

J4. 2011, 46(10):  86-98. 

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Organic spintronics is introduced from the points of ferromagnetic and non-ferromagnetic organic devices. The spin-dependent quantum transport and the microscopic dynamical progress of spin carriers in organic semiconductors are investigated. Especially, the latest discovered organic magnetic field effect (OMFE), including our theoretical investigations, are systematically summarized.

Research advances of novel nonlinear optical crystals based on second-order Jahn-Teller effects (SOJT)

ZHANG Jun-jie, ZHANG Zhong-han, TAO Xu-tang*

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2011, 46(10):  99-120. 

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Explorations of new inorganic second-order nonlinear optical (NLO) materials is one of the current frontier topics due to their optoelectronics application such as frequency shifting, optical modulating, telecommunications and signal processing. Since 1998, a series of noncentrosymmetric (NCS) and polar oxides containing cations susceptible to second-order Jahn-Teller (SOJT) distortions, specifically, octahedrally coordinated d0 transition metals (TMs: Mo⁶⁺,W^6+,V⁵⁺,Nb⁵⁺,etc.) and cations with stereochemically active lone pairs (SCALP, e.g. I⁵⁺, Te⁴⁺, Se⁴⁺, Sn²⁺, etc.), were successfully synthesized. Many of these materials exhibit large powder second-harmonic generation (SHG) efficiencies (> 400×α-SiO₂). This paper reviews the progress on the materials in the past decade, including the search for new materials and crystal growth. The materials are divided into three categories: NCS oxides containing one kind of SOJT cations (d0 or SCALP), NCS oxides containing both kinds of SOJT cations, and NCS oxides containing SOJT cations and other NCS building units such as borate πorbital systems, tetrahedral groups and d10 transition metal cations (Zn²⁺, Cd²⁺, Sn⁴⁺, etc.).

Nanoporous metals: a new class of nanostructured energy materials

DING Yi1,2

J4. 2011, 46(10):  121-133. 

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 Dealloyed nanoporous metals (NPMs) represent a new class of functional materials with unique structural properties such as high surface area, low density, high permeability, high electrical and thermal conductivity, and tunable structural features, which make them very attractive for important applications including catalysis, separation, and energy and environmental technologies. This article tends to provide an overview of the recent advances in this area, regarding their preparation, structure and interfacial properties. In particular, we will address their great potential as next generation electrode materials for new energy technologies.

Formation of particles@vesicle composite induced by solid particles

HOU Wan-guo*, NIE Hong-qian, DU Na

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2011, 46(10):  134-141. 

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Solid particles can induce the selfassembly of amphiphilic molecules in aqueous solution to form vesicles and composite of particles encapsulated in vesicle (particles@vesicle). The composite of particles@vesicle has a bright future for application in constructing supported lipid bilayers, stabilizing clay suspension, synthesis of materials with special structure and new drug delivery systems. In this paper, the formation of particles@vesicle composite and their applications were outlined.

Establishment of a human corneal endothelial cell strain and in vitro reconstruction of a tissue-engineered  human corneal endothelium

FAN Ting-jun, MA Xi-ya, ZHAO Jun, HU Xiu-zhong

J4. 2011, 46(10):  142-151. 

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To reconstruct tissue-engineered human corneal endothelium (TE-HCE) suitable for corneal transplantation, this study was intended to screen out monoclonal cell strains from a untransfected human corneal endothelial (HCE) cell line, and reconstruct TE-HCE in vitro by using these cells as seeder cells. Monoclonal cell strains were screened out from the HCE cell line by limit dilution. Results of morphology, structure and chromosome analysis, combined with the results of expression of cell-junction proteins and membrane transport proteins, suggested that the cells from mcHCE2401 monoclonal cell strains had steady and normal morphology, structure, karyotype, and positive expression of cell junction proteins and membrane transport proteins as well. All these imply that mcHCE2401 cells have ideal characteristics of seeder cells for TE-HCE reconstruction. By using mcHCE2401 cells as seeder cells, modified denuded amniotic membrane (mdAM) as scaffold carrier, TE-HCE was reconstructed. Results of morphology and structure examination showed that polygonal mcHCE2401 cells formed a continuous and intact monolayer on mdAM with extensive cellcell and cellmdAM cell junctions. The average cell density of the monolyer was as high as 3602.22±45.22cell／mm² (equivalent to HCE cell density of a 0～3 years old baby). All these indicate that the reconstructed TE-HCE had very similar morphology and structure to those of HCE in situ. In conclusion, a monoclonal cell strain with normal morphology, structure, karyotype and celljunction and membrane transport protein expression has been established, and “youngest”TEHCE with similar morphology and structure to those of HCE in situ has been reconstructed successfully in vitro and provides a promising equivalent of donated HCE for clinical treatment of diseases caused by corneal endothelial disorders.

Electron hopping transfer in proteins and structures of solvated electrons

BU Yu-xiang

J4. 2011, 46(10):  152-159. 

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Some new features of charge hopping transfers in proteins are reviewed in this article, which focuses on the structures and properties of solvated electrons, a possibly existing intermediate in the charge transfer processes in proteins, and their important role in assisting long range charge migration in proteins. Normally, there are a lot of groups, molecular fragments and electropositive zones in proteins, such as the protonated basic amino acid side chains, aromatic rings, polar peptide chains, helices and structuring water clusters, and so on, and they can capture and then electrons, playing a relay role in assisting electron hopping transfers. This kind of solvated electronbased electron hopping modes can be considered as a new pathway of longrange electron migration in proteins.
 

Progress in basic and technological research of enzyme system for lignocellulosics biodegradation

QU Yin-bo

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2011, 46(10):  160-170. 

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Research on cellulose biodegradation has been carried out for more than 50 years in Shandong University. Based on the mechanism studies on microbial degradation of lignocellulosics, a Penicillium decumbens strain, which can hydrolyze lignocellulose efficiently, was isolated from natural samples, and several catabolite repressionresistant mutants were obtained. Genome sequencing of the strains were carried out, and the composition of their enzyme system and the mechanism for regulation of enzyme synthesis were studied by systems biotechnological methods. The cellulase-overproducing mutants has been used for cellulase production in industrial scale, and for cellulosic ethanol production in biorefinery of corncobs.

The role of amygdala in pain and pain-related affective and cognitive disorders

JI Guang-chen

J4. 2011, 46(10):  171-177. 

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Pain, including persistent chronic pain, not only has a strong negative affection but is also intimately related to fear, anxiety and depression. The amygdala is believed to be a key subcortical structure involved in emotional affective behavior including the emotional responses to pain. Our recent studies show the evidence that amygdala plays a key role in pain and pain-related affective and cognitive disorders. 

Antibiotic resistance in food-associated lactic acid bacteria

KONG Jian, JI Ming-jie, YANG Pu

J4. 2011, 46(10):  178-182. 

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The emergence of antibiotic resistance in pathogens posed a major threat to human health because of abuses or misuse of antibiotics. Lactic acid bacteria (LAB) as starter cultures or probiotics were widely used in the production of fermented food and silage processes, and have acquired “generally recognized as safe” (GRAS) status. However, recently it was demenstrated that antibiotic resistance genes from foodassociated LAB strains were highly identical with that of pathogens, suggesting that LAB have the potential to serve as a host of antibiotic resistance genes with the risk of transferring the genes in commensal or pathogens in the intestinal gut. Antibiotic resistance genes were diveded into intrinsic resistance and acquired resistance based on their transferbility. Acquired resistance genes were often encoded by conjugative plasmids or conjugative transposons, which could enter into gastrointestinal tract through the consumption of fermented foods, and then transfer to the indigenous microflora and pathogens, furthermore resulted in the disease. This review will focus on the mechanism of resistance, detecyion methods of antimicrobial susceptibility and gene horizontal transfer of antibiotic resistance in foodassociated LAB.

Advances of gene knockout in mice

ZHANG Jian, YANG Xiao-mei*, GAO Jian-gang*

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2011, 46(10):  183-196. 

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With the successful completion of Human Genome Project (HGP),the biological research of postgenome era has a urgent need for an effective gene function analysis. Application of knockout mouse model provides a strong support for the study of gene function and the search for new therapeutic interventions in human disease. As two different techniques, gene targeting and gene trapping are producing knockout mice from embryonic stem cells (ES cells).The characteristic of gene trapping is highthroughput, random, and sequence tagged,while gene targeting is a specific gene knockout. Two decades ago, the first gene targeting and gene trapping mice were generated. In recent years, new tools for gene targeting and gene trapping are emerging, and the related organizations have been formed. These organizations can knock out genes in the mouse genome using these two methods. The international gene trap consortium (IGTC) and the knockout mouse project (KOMP) have begun to create a worldwide resource for research facilities, and plan to knock out all the mouse genes. KOMP organizers consider it as important as the HGP. From conventional gene targeting to high throughput conditional gene targeting, gene targeting methods have changed. The combined advantages of trapping and targeting enhance the gene trapping spectrum and gene targeting efficiency. As a newly developed insertional mutation system, transposons in trapping genes have more advantages than retrovirus. Emergence of the international knockout mouse consortium (IKMC) is the beginning of global cooperation. The organization is committed to systematically knock out all genes in the mouse genome, and then to carry out functional genomics studies.

Moving tawards Internationlization: the past, present and future of ecology discipline in Shandong University

WANG Ren-qing*,DU Ning,GUO Wei-hua,ZHANG Shu-ping,DAI Jiu-lan,LIU Jian,WANG Yu-zhi,WANG Yu-tao

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2011, 46(10):  197-206.  doi:Q948

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There is nearly a over 80 years history of Ecology Discipline in Shandong University. With the joint efforts of several generations of ecologists, Ecology Discipline based on the warm-temperate vegetation research and got continuous development and innovation. At present, with the leadship of Academician Zhang Xinshi and Professor Wang Renqing, the Ecology Discipline got into the stage of rapid development, and gradually formed several predominance and international research aspects and research fields: vegetation ecology and eco-physiology of the dominant species in the warm-temperate zone, plant genetic diversity and conservation biology, soil microbial ecology and soil pollution, ecological compensation mechanism and biological invasions, animal ecology, industrial ecology and ecological health, which have greatly improved its influences both in the domestic and international academic world. . In the future, the research group will continue to make great efforts to cooperate with domestic and foreign universities and research institutions, promote the development strategy of "Come in and Go Outside", highlight the characteristics of own research, and constantly improve the level of internationalization.